Wake up launcher when enabling a subscription

Otherwise one would have to wait up to DEFAULT_NAPTIME_PER_CYCLE until
the subscription worker is considered for starting.

There is a small race condition:  If one enables a subscription right
after disabling it, the launcher might not have registered the stopping
when receiving the wakeup signal for the re-enabling.  The start will
then not happen right away but after the full cycle time.

Author: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index c29a57ed52d2bb4c9bc7045b00213e23821b007c..6a404bbe1e3d18be28fad1a325e3466ae87fc45f 100644 (file)
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -644,6 +644,9 @@ AlterSubscription(AlterSubscriptionStmt *stmt)
                    BoolGetDatum(enabled);
                replaces[Anum_pg_subscription_subenabled - 1] = true;
 
+               if (enabled)
+                   ApplyLauncherWakeupAtCommit();
+
                update_tuple = true;
                break;
            }